Conventionally, in the fields of pharmaceuticals, foods, and other chemical industries, cellulose powder is widely used as an excipient for molding when a molded article containing an active ingredient is prepared. In addition, in the case where the active ingredient is a liquid ingredient, the liquid ingredient is carried by a single inorganic compound to obtain a powder. The obtained powder is molded into a molded article by using a cellulose powder as an excipient.
Unfortunately, the single inorganic compound has an excessively large apparent specific volume, which limits the amount of the active ingredient to be powdered at one time. There is also a handling problem such that the inorganic compound scatters, or the like. For this reason, use of cellulose-inorganic compound porous composite particles as the excipient has been examined.
Patent Literature 1 describes an invention of fine particles produced by co-processing a microcrystalline cellulose particle and calcium carbonate having a particle size less than 30 μm in a specific mass ratio in order to reduce cost of a pharmaceutical excipient.
Patent Literature 2 describes an invention of an excipient composition composed of a fine particle agglomerates including a microcrystalline cellulose and silicon dioxide as a pharmaceutical excipient having improved compressibility.
Patent Literature 3 describes an invention of cellulose inorganic compound porous composite particles which are an aggregate of a specific cellulose dispersed particle and a water-insoluble inorganic compound particle, and having an intraparticle pore volume of 0.260 cm3/g or more. According to Patent Literature 3, the cellulose and the inorganic compound are formed into composite particles to obtain a particle having a large intraparticle pore volume, and high compactibility, disintegration properties, and fluidity.
Patent Literature 4 describes an invention of a solid formulation which is not a composite product but a physical mixture of an inorganic compound and a microcrystalline cellulose, and comprises a drug, calcium silicate, and starch and/or microcrystalline cellulose, in which 10 to 45% by weight of calcium silicate is blended based on the drug, and 40 to 250% by weight of starch and/or microcrystalline cellulose is blended based on calcium silicate. According to the description, even if a drug having poor compactibility such as phenacetin and acetaminophen is directly tableted, 70 to 90 parts by weight of the drug can be blended without capping.